Jaw reduction is a type of aesthetic plastic surgery in which the objective of treatment is to narrow the lower one-third of the face—particularly the contribution from the mandible and its muscular attachments. There are several techniques for treatment—including surgical and non surgical methods. Jaw reduction is most commonly performed in Asia where there is a societal preference for a slender jaw profile.

Facial aesthetics

A square lower jaw is generally considered a very masculine trait. Widening of the lower third of the face can cause either a square appearance to the face as a whole or can distort the natural appearance of the angle between the chin and the neck.

Whereas square lower jaws are often considered a positive trait in Caucasian and many Asian men, a wide mandible can cause significant facial discordance and/or masculinization of the female face—particularly in those of East Asian descent. Even in certain men, the size of the lower jaw can cause facial disharmony—particularly when there is asymmetry.

A wide lower face can primarily be caused by enlargement of the mandible or masseter muscle.

Causes

The primary cause of an enlarged mandible is developmental or congenital. There are some rare disorders that can further widen the jaw such as acromegaly.

Conversely, while a masseter muscle can be large due to congenital reasons, it can commonly be an acquired deformity. Like any muscle it increases in size with exercise. Behaviors such as repeated gum chewing, teeth clenching, or bruxism can contribute to enlargement of the muscle.